If you merge in RG Notation beamed notes
e8 e8 e8
the beaming group is not changed. Instead, the beaming group should be always recalculated after a note merge.
Here the beaming group should disappear.
Strange results may appear when you merge for example notes in the middle of a group:
e8 e8 e8 e8
e8 e4 e8
In the example above RG notations shows flagged e8 in "e8 e4 e8". If these notes are in the same beaming group, e8 notes should have beams, not flags.
Erroneous beaming groups results in wrong beaming groups in LilyPond output for "e8 e4 e8".